1. Field
The disclosure relates generally to transmission of data via optical fibers and more specifically to transmitting coarse wavelength-division multiplexed optical signals over a standard multimode optical fiber by adjusting a data rate of each individual channel transmitted over the standard multimode optical fiber to match a modal bandwidth of the standard multimode optical fiber at the wavelength of each individual channel.
2. Description of the Related Art
Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. An optical fiber is a flexible, transparent fiber made of extruded glass (silica) or plastic. The optical fiber functions as a waveguide or light pipe to transmit light (i.e., optical signals) between the two ends of the fiber. Optical fibers are widely used in fiber-optic communications because the optical fibers transmit information at higher bandwidths (data rates) than wire cables. Optical fibers that support many propagation paths or transverse modes are called multimode fibers (MMF), while those that only support a single mode are called single-mode fibers (SMF). Typically, multi-mode fibers have wider core diameters and are used for short-distance communication links and for applications where high power must be transmitted. Single mode fibers are used for most long-distance communication links.
Multimode optical fibers are commonly classified as OM1, OM2, OM3, and OM4 based on the modal bandwidth characteristics of the fiber. OM stands for optical multimode. OM3 and OM4 fibers are laser optimized and may be used with vertical cavity surface emitting lasers (VCSELs), for example. VCSELs are capable of modulation over 10 gigabits per second (Gbits/s) and are used in many high speed networks.
The amount of data or bits that can be transmitted or processed per unit time over a fiber-optic communication system is referred to as the bit rate, data rate, or data throughput of the system. Traditionally, system bit rate and baud rate is increased by increasing the number of channels carrying data, increasing the bit rate of each channel, or both. In order to meet ever-increasing bandwidth demands, aggregate throughput in fiber-optic communication systems has conventionally been increased by using wavelength-division multiplexing (WDM), time-division multiplexing (TDM), or some combination of the two techniques. Wavelength-division multiplexing techniques increase the number of channels transmitted on a particular optical fiber, while time-division multiplexing techniques increase the bit rate of each individual channel. Wavelength channel spacing of more than 8 nm is generally called coarse wavelength-division multiplexing (CWDM) and typically utilizes wavelengths from 1271 nm to 1611 nm.